1. Field of the Invention
The present invention relates generally to powered edge trimmer devices and, more particularly, to edge trimmer devices attached to power lawnmowers.
2. Description of the Prior Art
When grass is cut, it is often desirable to trim edges of sidewalks, driveways, and the like. Currently, three types of edge trimmers are known in the prior art: a first has manually operated blades; a second has a power-driven blade in a separate and distinct edge trimmer device; and a third employs an edge trimmer device in conjunction with a power-driven lawnmower. With particular attention being paid to the edge trimmers associated with power-driven lawnmowers, throughout the years, a number of innovations have been developed, and the following U.S. patents are representative of some of those innovations: U.S. Pat. Nos. 3,686,839; 3,789,591; 4,378,668; 4,551,967; and 4,718,221. More specifically, each of U.S. Pat. Nos. 3,686,839 and 4,551,967 discloses an edge trimmer associated with a lawnmower wherein the edge trimmer is powered by the lawnmower by using a drive belt. It is well known that drive belts stretch and crack with age. Moreover, the drive belt must be used with accompanying pulleys. To eliminate the complexities associated with the use of drive belts, it would be desirable if a lawnmower-attached edge trimmer device could operate without using a drive belt.
U.S. Pat. No. 3,789,591 discloses a power lawnmower having an auxiliary flexible drive shaft for an edger head. A separate and distinct drive disk is provided above the lawnmower blade on the drive shaft. A spring-biased driven friction wheel is selectively placed in frictional contact with the drive disk. The friction wheel itself is part of an assembly which is pivotally connected to the body of the lawnmower. To avoid the use of a spring (which may fatigue) and to avoid the use of a pivoted connection (which may need regular lubrication), it would be desirable if a lawnmower-powered edge trimmer does not operate by using a spring or a pivoted connection assembly.
U.S. Pat. No. 4,378,668 discloses a lawnmower-powered edge trimmer which employs a plurality of whip blades which are kept in constant motion even when the blades are not being used for trimming. When retractable guards are retracted, the whip blades are permitted to extend outward to be used for trimming. When the retractable guards are returned to their original positions, the whip blades are once again prevented from trimming. It is wasteful of energy to keep whip blades in constant rotation even when they are not being used for trimming. For this reason, it would be desirable if a lawnmower-powered edge trimmer does not employ trimmer blades that are in constant motion, even when the trimmer blades are not being used for trimming.
U.S. Pat. No. 4,718,221 an edger and trimmer that is carried by a lawnmower body, but the lawnmower engine does not power the cutting action of the edger and trimmer. More specifically, a cutting disk that is selectively raised or lowered by an operator. When the cutting disk is raised, it does not contact the ground. However, when the cutting disk is lowered, the cutting disk contacts the ground and trims the grass as a result of the lawnmower being pushed along the ground by an operator. No power is tapped from the lawnmower engine to be sent to the cutting blades. Some grass will not readily be cut by a relatively slow moving cutting disk as described above that is not powered by the lawnmower engine.
Still other features would be desirable in a lawnmower-attached edge trimmer apparatus. For example, there are many lawnmowers currently in use that do not contain edge trimmer features. In this respect, it would be desirable if a conventional lawnmower could be retrofitted to provide a lawnmower-powered edge trimmer. With respect to retrofitting, conventional lawnmowers come in a variety of sizes. More specifically, the circumferences of the housings for the cutting blades of lawnmowers may differ from one lawnmower to another. In this respect, it would be desirable if a lawnmower-attached edge trimmer apparatus that is retrofitted to a lawnmower could be adjusted to a variety of sizes of lawnmower housings.
Thus, while the foregoing body of prior art indicates it to be well known to use lawnmower-attached edge trimmer devices, the prior art described above does not teach or suggest a lawnmower-attached edge trimmer apparatus which has the following combination of desirable features: (1) does not employ trimmer blades that are in constant motion, even when the trimmer blades are not being used for trimming; (2) can be retrofitted to a conventional lawnmower; (3) can be adjusted to a variety of sizes of lawnmower housings; (4) has a manually controlable connect/disconnect between the attached auxilliary trimmer apppartus and the main lawnmower drive; and (5) includes easy adjustment of the angular orienetation of the attached trimmer cutting blades or filaments to conveniently control the width of cut of the auxilliary cutting apparatus. The foregoing desired characteristics are provided by the unique lawnmower-attached edge trimmer apparatus of the present invention as will be made apparent from the following description thereof. Other advantages of the present invention over the prior art also will be rendered evident.